The primary purpose of the tax system is to finance government expenditure. The level of government spending generally provides the best overall measure of the tax burden. The Review should therefore focus, in the first instance, on the level of government expenditure that might properly be funded from taxation over the medium to longer term. We believe that a principled analysis of the role of the government, against the background of policies aimed at increasing the rate of economic growth and firm fiscal discipline, would conclude that a substantially lower level of government spending is required in the future.